Stereoscopic apparatus in relation to cinematograph reproduction and television



Nav. 5, 1946. A

STEREOSCOPIC APP'ARAT REPRODUCTION AND TELEVISI Filed Aug. 25, 19442,410,725 OCINEMATQGRAPH P. FRANKLIN US IN RELATION T0 1l Sheets-Sheet lNov. 5, 1946. A. P. FRANKLIN 2,410,725

STEREOSCOPIC APPARATUS IN RE LATION TO CNEMATOGRAPH REPRODUCTION ANDTELEVISION Filed, Aug. 25. 1944 11 sheets-sheet s A. P. FRANKLlN 4lsTEREOscoPIc APPARAT RELATION To OINEMATOGE AND TELEVISION 11Sheets-Sheet 4 Us IN REPRODUCTION Fil'ed Aug. 25, 1944 Abw firm/fwn'.

Nov. 5, 1946.

A. P YFRANKLlN 2,410,725 STEREOSCOPIC APPARATUS IN RELATION TOCINEMATOGRAPH REPRODUCTION AND TELEVISION Filed Aug. 25. 1944 11Sheets-Sheet 5 NOV. 5, 1946. I A p FRANKUN 2 10,7254

9 STEREOSCOPIC APPARATUS IN RELATION TO CINEMATOGRAPH REPRODUCTION ANDTELEVISION Filed Aug. 25. 1944 11 Sheets-Sheet 6 'Si s y I N ce: QB [n Nm *i l N E Zvvfwro/,P

A. P. FRANKLlN 2,410,725 STEREOSCOPIC APPARATUS IN RELATION TOCINEMATOGRAPH v Nov. 5, 1946.

REPRODUCTION AND TELEVISION 4 l1 Sheets-Sheet 7 Filed Aug. 25. 1944 v.lww M T T H Nov. 5, 1946. A P. FRANKLlN 2,410,725

sTEREoscoPIc APPARATUS 1N RELATION To GINEMATOGRAPH 1 REPRODUCTION ANDTEI..\.':vIsIoNI Filed Aug. 25, 1944 11 Sheets-Sheet 8 yy, im

)WTO/May.

Nov. 5, 1946. l11.1. FRANKLIN 2,410,725 STEREOSCOPIC APPARATUS INRELATION TO CINEMATOGRAPH REPRODUCTION AND TELEVI S ION Filed Aug. 25,1944 11 sheets-sheet 10 NW 5 .1946 A. P. FRANKLIN 2,410,725

STEREOSCOPIC APPARATUS IN RELATION TO CINEMATOGRPH REPRODUCTION ANDTELEVISION Filed Aug. 2s. 1944 11 sheets-sheet 11 www@ v Patented Nov.5, 119.4596

STEREOSCQPIC APPARATUS 1N RELATION TO `CINEMATGGIRAPH REPRODUCTIQN ANDTELEVISION Alan Philip Franklin, Lower Kingswood; England ApplicationAugust 25, 1944, Serial No. 551,128 In Great Britain August 31, 1943This invention relates to stereoscopic apparatus for viewingstereoscopic pictures and in particular to moving pictures resultingfrom cine- /matograph or television reproduction where a number ofpeople have to view the same picl torial reproduction.

One of the difficulties experienced with the design and construction ofany apparatus suitable for use bythe public is that the average memberof an audience will not use any device as an aid to vision which has .to.be held or manipulated continuously during a performance or which mustbe held close up to the eyes.

Another ditculty is that in stereoscopic reproduction any movement cithe viewer which moves' the eye-pieces of the viewing device out of theplane passing through thecentres of the two pictures destroys fusion andthe stereoscopic eect is at once lost. If the device is held or worn bythe viewer the necessary restraint would be most irksome, whereas whenthe device is mounted in the manner described hereinafter in relation tomy own invention this diculty is overcome.

In the application of polarised light it has been suggested to providespecial spectacles for viewlng, but the drawback to the provisionof-glasses or other unattached device is that, apart from the expense,they are liable to become damaged or lost. If, however, they are made axture and somewhat inexible control of focus and convergence they canproduce currect' fusion of the two images without strain.` y

By use of a very complicated system oflmultll ple lenses and concavemirrors, individual aids to vision might possibly ybe dispensed with,but at a vprohibitive cost.

Persons using my apparatus in the'home, could move their viewing pieces,and fixtures erected on a suitably weighted stand to any position tosuit the angle of the prism. Prisms could be changeable but would bechosen for a normai distance from the television set so that 3'or morepeople can view it at the same time.

A very few people can,

front of the viewer the two eye pieces will always be maintained withtheir axes in a plane passing through the centres of the two pictures.

The device may be made of metal, cardboard or one of the well-knownplastics or-any other suitable material. The device can be moved toConform to any movement of the Viewer.

In thesimplest form no, lenses or mirrors are needed for this invention.The probability is that only one prism will be necessary. y I

The device could also be used in the case of polarised light where thepictures to be viewed are superimposed. For this purpose a polarisnglter would be itted to each eye piece and the prism or prisms moved outof the line of vision. Y The drawings which will now be referred to showthe `stages of development of the invention.

Fig. 1 is a perspective diagrammatic view of one form of apparatus madeaccording tothe present invention. I

Fig. 2 is a part sectional plan view of another form of device madeaccording to the present invention.

Fig. '3 is a cross-section on the line 2 2 of Fig. 2 looking inthedirection of the arrows.

Fig. 4 is a front view of the cap shown in Fig. 2.

Fig. 5 is a front .view of the device illustrated in Fig. 2 on a reducedscale to show part of the method of mounting.

Fig. 6 is a side view showing the complete device with mounting.

Fig. 7 is a sectional plan view of a modified form of the device shownin Figs. 4, 5 and 6.

Figs. 8 and 9 are end views of the device shown in Fig. 7.

Fig. 10 is a longitudinal sectional elevation of the device shown inFig. 7.

Fig. 11 is a sectional plan view of one form of device made according tothe present invention.

Fig. 12 is a cross section on the line 2'2 of Fig.-

11 looking in the direction of the arrows.-

Fig. 1'3 is a front view ofthe device illustrated in Fig. 11. a

Fig.' 14 is a side v iew on a reduced scale showing the complete device'with mounting.

Fig. 15 is aplan of Fig. 14.

Fig. 1'6 is a sectionalp'lan view of a inodiiiedV l form of the device.

Figs. .17 and 18 are front and side elevations respectively of thedevice shown in Fig. 16.

Fig. 19 is a sectional plan view.

Fig. 20 is a transverse vertical section through i one of the prismholders, and

. As the device is xedly supported in position in /s Fig. 21 is apsBil.vl l

an elevation sione' of the butterfly 'l is provided to assistmanipulation, and the de- A vice is maintained in'position by tighteningall pivotsor other adjustable parts. A pair of eye pieces tted withprisms 9 are arranged in relation to the bar I and are encased in amanner similar to the eye pieces of a stereoscope.

The bar I is made of such dimensions that 'if adjusted to its normalposition it will block out the view of the right-hand picture from theleft. eye and vice-versa so that the right eye of the viewer will onlysee the right-hand picture and the left eye the left-hand picture.

The operation of the device will be obvious from the drawings, thereforeno further description will be given.` s

The arrangement will avoid discomfort of any attachment which has to beworn and, as will be seen, the eye pieces are of such a size as toenable them to be positioned at from three to six inches from the eyesof the viewer whilst permitting a full and correct view of therespective pictures to be obtained.

Referring to the construction shown in-Figs, 2 to 6, the devicecomprises an outer casing a similar in shape to the eye mask of astereoscope. Pivots b provided with wing nuts c are secured to andextend laterally from the casing toengage supporting arms d. Mountedwithin the outer casing a are inner casings e and e' which are providedwith pivots .f slidable in slots g in the outer casing and secured bythumb nuts h. The inner casings e and e' carry detachable ared tubes 7'and y" which are secured against unauthorized' removal by light chainsshown in Fig. 6 ('25). Within the outer casing a is mounted an aperturedpartition lc adjacent the ends of the tubes j and 7". The tube e isprovided with a prism m whilst the tube e' may be open-ended or providedwith a piece of plane optical glass to keep out draughts. The end of thetubes i 7" are closed by a cap n having an eccentric aperture shown indetail in Fig. 4.

Referring tothe construction shown in Figs. '7 to- 10 inclusive, thisform of the device comprises a box-like outer casing I of substantially.rec

tangularr cross-section two ends of the box being left open. One end isshaped to form an eye mask 2. Portions 3 of the side walls adjacent theother end are removed and replaced by shutters 4 hinged at 5 the saidshutters having upper and lower flanges which t into the casing I and byfriction therewith hold the shutters in the de-- -aperture thereof is a.detachable prism holder IllV provided with prism ll the holder beingslidable laterally and pivoted in the same manner as in the form shownin Figs. 2 to 6. A similar holder may be provided in front of the otheraperture and carry plane glass tov exclude draught.

The most convenient position for mounting the 4 device in the case of acinema would be from the hack of the'front seat and slightly to one sideto avoid the head of the front seat holder. They' can be on either hisleft or right or alternated according to circumstances, or the mountingcan be accommodated in the recess between two seats and drawn out to therequired position. A

The mounting as shown in Figs. 5, 6 and 8 mainly comprises a standard 28pivoted to a slide 22, the slide being capable of adjustment in alateral direction,- and the standard adjustable in. a verticaldirection. The slide 22 enables the apparatus to be moved to conform toany lateral movement of the viewer. The apertures in the eye-pieces asseen in Fig. Bare elongated to allow for his movement up and down. Afterthe device has been correctly positioned the various adjustable partsmay be locked by a wing nut or a clamping device. The tting arrangementof the tubes as shown in Fig. 6, comprises a fork 23 which receives thetransverse pivot 24.

In order to avoid loss of parts all parts are made so that nothing canbe detached, although they can be loosened for purpose of adjustment.

.The arrangement as shown in Fig 6 enables the for each tube. In Fig. 7,however, ajustable shutters 4 and 'I are provided to serve the samepurpose. Of course, foreach seat a different aperture can be xedlyprovided. Thi:J would obviate any adjustable apparatus.

In order to reduce the cost one prism only need be used and this can belocated in one of the tubes, the other being left clear, preferably theright. The angle of the prism would naturally be selected according tothe position of the seat from which the pictures are to be viewed, butit has been found in practice that a prism of about 20 willgive perfectfusion in the greater part of the auditorium so that special prismswould only 'l be required for a small number of seats.

Minor adjustments may be effected by moving the apparatus nearer orfurther from the eye, the major adjustment .being obtained by the prism.

In most cases the more important adjustments can `be effectedpermanently for each seat, leaving only a' few minor adjustments to becarried out by the members of the audience, which will only be of thesimplest kind. y

No new equipment will be required for projection as the complementarypictures are arranged side by side on the film and projected through thesame lens.

In order to make use of the same size frame as is now used in practicethis area may be divided v v vent unauthorized withdrawal.

pictures together will be 30 and the height 10.

That means that the fused picture will be x 10'. On the other hand, ifthe two pictures are taken square on the normal lm, they could beprojectedwithout the 90 prism, to make a fused picture of 10 x 10'. Ifthe cinemas will not enlarge their screens, so as to make them v30 long,the latter arrangement can easily :be carried out.

Furthermore, if the square lms, which I contend, and, as I have provedby tests, with third dimensional vision would be quiteA appropriate, areobjected to, the picture rwould have to be one quarter the size of thenormal picture assuming also that is the maximum breadth available forthe two pictures.

Referring to the form shown in Figs. 1l to 13, the device comprises ahollow body part or casing I having a mask portion 2 cut away to theapproximate shape of the forehead and, therefore, somewhatsimilar inshape to the mask of the well-known stereoscope. The device according tothe present invention however, diiers es- Forward of the guides s thesides of the body I are inclined outwarlly and terminate in pivotedshutters I4 of opaque material having actuating members through arcuateslots I6 in the bottom wall of I5 secured thereto which extendthe :bodyl a friction device or other means (not v shown) being provided to holdthe pivoted shutters I 4 in position after being set. In a similarmanner the central partition 6 terminates in two pivoted shutters I1with actuating members I8 extending through arcuate slots I9. Secured tothe bottom wall of the body.I near the point of.

balance isa bifurcated lug 20, the wings of which are drilled at 2l, toreceive a rivet or bolt 22 shown dotted in Fig. 13.

In the drawings the prisms III are of relativelyy h v large angle and itis to be understood that such plane glass. The use of a singlet-prismwill reduce cost of manufacture.

sentially from a stereoscope in that the viewer should not press hisforehead against the device or vice versa and should on the contraryalways arrange the device so that-it is clear of his forehead by a fewinches. The mask portion 2 therefore only acts as a shield or shade toshut out unwanted light or views and so aid concentration. v

Slidably mounted in the body I adjacent the mask 2 are two shutters ormovable blocking pieces 3, carried in guides 4, the shutters 3 extendingthrough slots 5 in the body I, so as to be manually operable fromoutside the body I. Each slidable shutter 3 is formed from a sheet ofopaque material of rectangular shape to slide in the guides @and isprovided with .a rectangular aperture two inches square, the inner edge'of which is spaced one inch from the edge of the shutter. I The twoslidable shutters are arranged to be able to'overlap at their inner endsso that the opaque end portions of one inch width may overlie oneanother. l

Arranged longitudinally down the centre ofthe body I and extendingforwardly from adjacent the guides 4 is a central partition yIi ofopaque maf terial. Fixed to the central partition 6 adjacent the guidesd is an opaquetransverse xedblocking piece 'I which is also of opaquematerial and one inch wide being bisected by the central partition 6.

Also mounted in the body I between guides 8 are prism mounts 9 holdingthe plane two inch V;

prisms Iii, the prism mounts 9 being provided -with an extension IIwhich extending for the full depth of the prism and being made of opaquematerial serves the dual purpose of a handle and a lightexcluder. Theside walls of the. body I are apertured at I2 to the full width of theprism mount 9 to enablel the mount 9 to be withdrawn for the purpose ofchanging or'cleaning the prism ID. Stops I3 which may be soldered orotherwise locked to the body I are provided to limit the outwardmovement of the prism mounts Sand precarryinga linked frame the Turningnowy to Figs. 14 and 15 of the drawings which show one formV ofadjustable mounting which enables the device to be moved to the desiredposition whilst guarding against its being tilted sideways. l I

Mounted on the back of the seat 30 is a bracket 3| pivotally supportinga 'ertic'al member 32v embers 33 to 33 of which form two coupledparallelograms theouter vertical member 38 carrying avertical socket 39in which is pivotally supported a pin Ml formed with a lug adapted toenter between the wings of the bifurcated lug 20 arid drilled to.receive the rivet or bolt 22.

Figs. 14 and 15.show clearly the movements which may be imparted to thedevice and its support. It will be obvious from Fig. '14 how the de-`vice can be raised or lowered, drawn towards the viewer' or pushed awaywhile Fig. 15 shows by dotted lines how the whole support may be swungsideways to conform to the regulations of the London County Council orother local authority, by pivoting about the member 32 or directedangularly by turning the device about the pivot 39. Fig. 14 also .showshow the device may be tilted about the rivet or bolt 22. It should benoted that this varrangement entirely prevents any sideways tilting.

'I'he device above described is best suited for use where the viewergets a relatively clear space between two members oi' the audiencesitting in the seats immediately in front. In some cinemas the seats arenot so well arranged. In such cases the seats should be rearrangd or thescreen raised. If `this is not-possible then the alternative but moreelaborate modified construction shown in Figs.1`6, 17 aid 18 may beemployed. In these figures the same reference numerals have been used todenote the same partsy `\Ir\1- stead of direct vision,\"p'airs ofmirrors 5I and 52 set in adjustable mountings so that their angularitymay be adjusted about pivots 53 to suit Athe -seat from which the screenis to be viewed. Only very small angular adjustment would ever berequired and the arrangement such that members of the public would notbe able to alter the angularity once it had been set for the requiredaccurate fine pensed with.

able shape.

with that shown in Figs. 11 to 13 except that a single prism I is shownon the right-hand side and a piece lof plane optical glass 53 on theleft side. Two prisms may, of course, be used and in this constructionas the' mirrors can be adjusted to produce fusion the use of a prismcould `be dispensed with. However, the adjustment of the mirrors -beingvery delicate, a more rapid and adjustment can be secured empirically bychanging the prism for one of a different angle.

Turningnow to Figs. 19 and 20 which show the latest and most simpliiiedform of the device which was evolved from that illustrated in Figs., 11to 13 of the drawings. Wherever possible the lsame'referencenumeralshave been used to ndicate the same parts as in Figs. 11 to 13, and onlythe differences will be noted.

The following diierences will be noted;

1. The central front,laps l'l have been dis- 2, The shutters` |4 havebeen lengthened and the pivots made a good rm it so that the pins I5 andslots i6 are norlonger necessary.

3. Instead of the sliding shutters 3 a pair of hinged butteriiy shutters6D are mounted on the partition 6 within the mask 2, the hinges beingmade stiff so that the buttery shutters 60 remain in the position inwhich they are set.

4. The blocking piece l has been omitted.

5. The prisms ID are nearer the eyes.

6. The top and bottom of the mask 2 are not cut away and so cover thebutterfiy shutters 60.

7. Stops I3 to prevent removal of the prism holders are formed on theinner end of the prism holders instead of on the casing as shown inFigs. 1 to 6.

8. The prism mounts have been modified to ensure a smooth sliding actionand a steady mount, as will be seen-from Fig. of the drawings ledherewith. 9. The sides of the device Y have become straightened toreduce the number of corners and simplify construction.-v It may befound that without the blocking piece when the prism or glass holders 9are drawn out slightly for adjustment light is admitted in the centre.It is probable that the butterfly shutters 60 when opened -out to thecorrect extent will exclude this Vunwanted light fromthe eyes. If not,it would be an easy matter to provide extensions at the inner ends ofthe prism holders 9 which will slide through slots in the centralpartition 6 and overlap each other when the prism holders are pushed intothe full extent. These extensions should not need to be more than1/2f' wide.

As will be seen fromFig. 21\,the top and bottom corners of the free edgeof the butterfly ap B0 havebeen rounded off. This avoids sharp cornersand is found in practice to be the most suit- Io enable the device tobeused in the home in conjunction with television sets, the support maycomprise a weighted pedestal which can be stood on the ground in thedesired position.

For use in a cinema the device will be equipped with all adjustmentssetaccording to the distance from the seat tothe screen and the anglesubtended by the two pictures so that for normal j Y vision perfectfusion would be obtained. Whichever form of device is installed theviewer after taking his seat and making himself comfortable will drawthe device down and 'towards him until it is only a few inches in frontof his face and will vset it angularly to direct it onto the screen. Hewill then make such adjustments as may be necessary to ensure that withhis left eye he can see only the left hand picture andwith the right eyeonly the right hand picture. It will be found that quite an appreciablemovement of the head may be made without much ioss of vision. Theshutters Aand prisms may be pre-set for normal y us'e and will onlyrequire adjustment so that the 10 pictures fuse in the most comfortableposition. 1 It may also be necessary to make a slight adjustnient of theprism or prisms lll by sliding them in or out in order to look throughthe/icentre of the prismas some people are much 'wider between the eyesthan others. Once set, however, no further adjustmentV is necessary. Ifanyone wishes to pass or if the viewer wishes to leave or, in the caseof an emergency, the device can be swung instantly out of the way.

The iixture will be such that if the viewer wishes to lean over to oneside or alter his position in any way, he can bring the device with him,by the very slightest movement of the instrument or the xture. He willin most cases be able to continue to view the pictures without anyfurther adjustment, having drawn the device to the most comfortableposition in front of the eye as before. With some kind of angie-poise"fixture this is an easy matter.

A further advantage is that as the device is supported at a reasonabledistance from the eyes the viewer if obliged to wear spectacles may doso without inconvenience.

For the sake of convenience and when time permits the device when out ofuse should be (a) It can be employed with private televisionl sets beingsuitably mounted in a fixed relation.

(b) It may be used in a cinema for viewing stereoscopic picturesprojected on the screen for a lm projector. (c) With suitablemodifications and adjustments it can be adapted for use withcomplementary pictures arranged side by side in the normal manner ofviewing stereoscopic pictures or it can be used for viewing superimposedpictures, separation of the two pictures being obtained by the bi-colourknown process (which cannot-at present be used for viewing stereoscopicpictureslin colour). or the use of polarised light, the device beingprovided with red and green glasses or polarised lters in the alreadywell-known manner for effecting separation of such pictures in place ofthe prisms. The prisms or plain glass eye-pieces could be removed andthe necessary eye-pieces inserted. j

If a member of the audience does not wish to see stereoscopically butwishes to view one picture normally without any aid to vision, the prismor prisms would have to be drawn out of the line of Vision, and the lineof vision from the two eyepieces confined to'one picture which, in thelatest device, is secured by closing the front shutters so 'I0-that onlyone picture can .be seen either through plain glassor direct. In thecase of the earlier tubular construction this, would be effected bypivoting both tubular extensions to direct them both onto the samepicture. Some seats could be kept for this purpose.' preferably theoutside A home for a television set. f

seats of the stalls, where practice has shown that the stereoscopicee'ct is not quite as arresting.

It is intended that in the design finally adopted for production everyreasonable measure will be adopted to render the device foolproof and to`guard against loss or damage or the removal by unauthorised persons ofthe device or any of the parts thereof.

For the purpose of photographing the pictures to be viewed an ordinarycinematographic camera can bevused, and one way of converting it to takestereoscopic pictures is to fix a simple at? tachment to the lens of thecamera. This attachment will consist of a .box-like member the aperturesof which (at each end) will be the size of .the lm to be taken but therewill be a partition down the centre. From each side of this partirtiontwo tubular members diverge to eye distance apart. In the ends of ythesetubes prisms are placed and two parallel extensions connected to v thetubes are positioned to face the direction of the box-like structureabove described. The angle between the end tubes and the divergent tubescan be as large as possible yand the degree of're fraction of the prismslcorrespondingly small.

The prisms can be made of glass, plastics or other material such asperspexand this can equally apply to the pri-sms in the viewing orprojecting device. This method of converting the oinematograph :camerainto an apparatus capable of taking stereoscopic pictures will be bothsimple and inexpensive.

, Some or all of the following advantages are claimed for the variousforms described:

1. It is the only form of stereoscope known for viwilg pictures at adistance or more than about a oo 2. No focussing is required when usedin a cinema because the prism lused is not a lens. When a lens is usedthis is one which does not require focussing.

3. The prism angle is selected according to distance and size or pictureto be viewed. 4. Only one prism is required in most cases.

.the viewing apparatus, the necessary magniflcation being fully providedby the projector` The prism used is .therefore plain glass and/nofocussingis required. It has been possible thus to overcome the dimcultythat has so often' presented itself in dealing with this problem,namely, how to combine focus and fusion in a stereoscope made forviewing at a distance. It has always been laid down that for perfectstereoscopy fusion and magnincation mus-t both be included in the.

viewing apparatus. A prism which did not embody a magnifying lens wastherefore abandoned as useless many years ago in making inalstereoscopes.

What claim and desire .to secure by Letters Paten-tis:

l. Stereoscopic apparatus for viewing' adjacent pictures at a distance,comprising, a viewing dethe origvice having two sight openings and meansfor" effecting fusion in the eyes of the viewer, of the images seen byhis two eyes therethrough, and anadjustable fixture supporting saiddevice, a socket member adapted to be secured to a xed support, avertical member pivotally mounted therein, a jointed frame pivotedthereto, for parn tial rotation-in a vertical plane and having anhorizontal joint permitting adjustment -of the outer part of said framein said plane towards and away from said socket member, a vertical pinrotatably mounted in the outer part of'said frame, and means forpivotally mounting said device upon said pin for angular adjustmentrelative thereto about an axis parallel to aline joining the centres of saidsight openings.

2. stereoscopic apparatus for viewing adjacent pictures at a distance,comprising, a viewing device having two sight openings and means for yeiecting fusion inthe. eyes of the viewer, of the 5. The onlystereoscope in which blocking pieces and apertures are adjustable. Suchadjustments may be xed for each seat and there need be n furtheradjustment.

6. The device i-s a fixture requiring no holding or wearing and need notbev positioned close to the eyes, but viewed at any distance up to thatof about 6" from the prism. 'Ijhe fixture arrangement is novel for acinema as well-as in the r1.v As a is a more the stereoscopic effect isnot choose his vown distance, whereas the usual stereoscope has smalleye-pieces and must be viewed closeup. 9. Anyone who has towearspectacles can do to images seen by his two eyes therethrough, andan adjustable fixture supporting said device, a socket member adapted tobe secured to a fixed. support, a vertical member pivotally mountedtherein, avjointed frame pivoted thereto, for partial rotation in avertical plane and having an horizontal joint permitting adjustment ofthe outer part of said frame in said plane towards and away from saidsocket member, a vertical f pin rotatably-'mounted in the outer part ofsaid frame, and means for pivotally mounting said device upon said pinfor angular adjustment relative thereto about an axis parallel to a linejoining the centres of said sight lopenings whereby' l*said viewingdevice is .movable in any desired direction within the limits permittedand i" maintained with the eye pieces for the two :ies of vvice havingtwo sight openings andmeans for effecting fusion in theeyes of theviewer, of the images seen by. his two eyestherethrough, and

\ 1l anadjustable xture supporting said device, a socket member adaptedto be secured to a xed support, a lverticalmember pivotally 'mountedtherein, a jointed frame pivoted thereto for partial rotation in avertical plane and having an horizontal joint permitting adjustment ofthe outer part of said frame in said plane towards and away from saidsocket member, a vertical pin rotatably mounted in the outer part ofsaid frame, and means for pivotally mounting said de-` vice upon saidpin for angular adjustment relative thereto about an axis parallel'to aline joining the centres of said sight openings, prisms for said viewingdevice, means enabling said prisms to be interchangedA whereby theapparatus is usable from any part of an auditorium of a cinema.

one-half diopter and mounted in the line of vis- Y ion of one eye.

5. stereoscopic apparatus for viewing adjacent pictures at a distance,comprising, a viewing de- 4. Stereoscopic apparatus for viewing adjacentpictures at a distance, comprising, a viewing device having two sightopenings and means for effecting fusion in the eyes of the viewer, ofthe images seen by his two eyes therethrough, and an .adjustable xturesupporting said device, a socket member adapted to be secured to a fixedsupport, a vertical member pivotally mounted therein, a jointed framepivoted: thereto, for partial rotation in a vertical plane and having anhorizontal joint permitting adjustment of the outer part of said framein said plane towards and away from said socket member, a vertical pinlrotatably mounted in the outer part of said frame, and means forpivotaily mounting said device upon said pintor angularadjustment-,relative vice having twosight openings and means foreiecting fusion in the eyes of the viewer, of the images seen by his twoeyes therethrough, and an adjustable fixture supporting said device, asocketmember adapted to be secured to a xed support, a vertical memberpivotally mounted thereirna jointed frame pivoted thereto for partialrotation in a vertical plane and having an horizontal joint permittingadjustment ofthe outer part of said frame in said plane towards and awayfrom said socket member, a vertical pin rotatablymounted in the outerpart of said screen is required and only half the area of the normalsize of each individual frame, and' rhalf the area of the screen beingused, provided y the usual proportion of length to breadth of the isretained.

individual picture ALAN PHILIP FRANKLIN.

